Sand Filter Draining When In "Filter" Position

The water is draining out of my sand filter when it is in the filter position.

Thanks for the question

The question didn't mention a general leak, just that the sand filter is losing water, so we'll start from there.

There could be many reasons why a sand filter leaks, but we'll start with the obvious.

Check the air bleeder valve and make sure it's seated correctly. There might be an O-ring on it. You can take the valve out and inspect it. Change the O-ring if damaged or broken.

Check the top of the filter for leaks. A bad O-ring might be the problem.

Depending on what kind of sand filter you have, you can check the bulk heads. This is where the water goes in and out of the filter. They're called the "Influent" and "Effluent". Water in and water out.

Look around the ground for wet spots. You may find the leak problem with that.

Your Multiport valve might be the problem. You can check the O-ring and replace that if needed. If the valve is bad, replace it.

Switch to another valve position. The valve should "click" into place. If it doesn't, you might need to replace it.

Check the pool pump O-ring and replace that if needed.

If this doesn't help you can email back with more details so I can help a bit better.

Good luck


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Swimming Pool Sand Filter Leaking Out The Drain In Filter Position

by RON
(meridian idaho)

I replaced my swimming pool sand and cleaned out my valve. Now when I put my Multi-Port valve on backwash some water still goes into the pool.

When back flushed the same thing happens, and not a lot of water goes out the drain line as it once did.



Thanks for the question Ron

New sand will have dirt and debris which will make itself through the filtration system and back into the pool. This is normal and will decrease as the sand settles and is used.

Be sure you're allowing about 10psi over "just backwashed" pressure before you backwash. Swimming pool sand filters need a little bit of pressure to operate correctly.

Take a look once again at the Multi-Port valve to be sure it's in proper working order. Are there any gaskets (spider) or O-rings that need to be replaced? Are all the screws tighten down? Is the valve "clicking" in the right positions, are do they "slide" in. If they slide you might want at either replacing the diaphragm, gaskets, or the entire valve.

Check to be sure you used the correct size sand (pool filter media) and the right amount of sand. Look at the owners manual for the amount of sand your filter needs and also the depth in inches from the top of the sand to the top of the filter.

You may have broken some laterals while replacing the pool sand. With that you'll need to scoop out the sand, replace the laterals, then carefully add the sand back into the sand filter.

After you backwash be sure to use the "RINSE" setting on the Multi-Port valve. Sand gets trapped in the lines after backwashing and not doing a rinse will cause the sand to go back into the pool.

Also check the valves for the drain and skimmer. If they are broken or worn you'll need to replace them.

Best of luck with your pool and have a great Summer


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Sand Returning Back To Pool After Replacing With New Sand

by Julie
(Perth, W. Australia)

We have replaced the sand in the filter, but when turning filter on after backwashing the sand returns to pool. We have had the laterals checked and have been told they are fine.

We have replaced the multi port valve but still have sand pouring back into pool.

Please help. This little problem has so far cost me in excess of $400.

Is there suppose to be a O-ring at the bottom of the multi port valve?

We have a Onga 3 way muiltport valve on a FMF20 sand filter.

Thanks for the question Julie

When you put new sand in a sand filter you will always get some sand going back into the pool. I replaced the sand in the sand filters at the YMCA and had to vacuum 4 times per week for two weeks before it stopped. It's a pain but that's what happens when you have a sand filter.

The question said the laterals are fine so no need to go there. Many times a broken lateral will cause sand to enter back into the pool.

Check the Multiport Valve and all the gaskets and O-rings. Your Onga valve is manufactured in Australia so getting those parts or questions answered shouldn't be a problem.

You may have accidentally dumped the sand into the filter without covering the stand pipe coming up from the bottom middle of the filter. The sand might stop going back into the pool as it is consumed.

The stand pipe might be full of sand and will take a while to clear up. Or you could keep vacuuming until it clears up, but that may take some time.

You could start over again by opening the filter, remove all the sand, and remove the stand pipe and clean it out.

Once you've cleaned and/or replaced the stand pipe, you need to plug it up. You can call the manufacturer for that part and refill the filter with #20 silica sand, or the sand media your filter recommends.

If you talk to the manufacturer, ask what the "freeboard" for the sand should be. This is a measurement from the top of the sand to the top of the filter. This way you'll have two pieces of information; the amount of sand you need and also the measurement. It should be around 10 inches.

After you have added all the required amount of sand, clean the seat and o-ring area before mounting the valve.

Fill the filter with water and start the filter in the backwash position and run briefly to clear it. Stop the pump and rotate the valve to "RINSE" to clear the lines. Stop the pump and return the valve to "FILTER".

Hope this helps and good luck with the filter


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